Primary stability with osseodensification drilling of dental implants in the posterior maxilla region in humans: A systematic review.

Currently, a new non-subtractive drilling technique, called osseodensification (OD), has been developed. It involves using specially designed drills with large negative cutting angles that rotate counterclockwise, causing expansion through plastic bone deformation, thus compacting the autologous bone to the osteotomy walls, which improves the primary stability of the implant.The present systematic review aimed to determine whether the OD technique can increase the primary stability of dental implants in the posterior maxilla region as compared to the conventional drilling (CD) technique.Five databases were searched up to June 30, 2022. The inclusion criteria embraced observational clinical studies, randomized and non-randomized controlled trials, human studies in vivo, comparing OD and CD, with the measurement of the primary stability of implants in the posterior maxilla region by means of the implant stability quotient (ISQ). The tools used to assess the risk of bias were RoB 2 and the NewcastleOttawa Scale (NOS).Seven articles met the inclusion criteria, with 4 classified as having a low risk of bias and 3 with a moderate risk of bias. The OD technique consistently demonstrated an average ISQ value of 73 KHz across all studies, whereas CD yielded an average value of 58.49 kHz (p < 0.001 for 5 articles).It can be concluded that in comparison with CD, OD improves primary stability at baseline in low-density bone, such as the maxilla.

Correlation Between Implant Stability Quotient and Percussion Sound Frequency.

OBJECTIVES: To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency. MATERIALS AND METHODS: A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded using a wireless microphone connected and analyzed with frequency analysis software. RESULTS: Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences in primary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone. CONCLUSION: The primary ISQ value and the percussion sound frequency are positively correlated.

Comparative evaluation of osseodensification drilling versus conventional drilling technique on dental implant stability: A systematic review.

AIM: The present systematic review compares the stability, crestal bone levels and efficacy of osseodensification (OD) drilling techniques for dental implant placement to traditional drilling methods. SETTINGS AND DESIGN: The Cochrane online library, PubMed, Scopus, and other well-known online resources are used in the research. Using a systematic review design, the current study examines published qualitative studies with an emphasis on analysis. MATERIALS AND METHODS: Using precise keywords, a thorough search of pertinent databases was carried out in accordance with PRISMA standards. Studies testing dental implant stability, crestal bone levels and clinical results using both OD and traditional procedures were covered by the inclusion criteria. STATISTICAL ANALYSIS USED: The risk of bias and quality of included studies was assessed using the Newcastle-Ottawa Scale for observational studies and the Cochrane Risk of Bias tool for randomized controlled trials. RESULTS: A total of 170 patients and 334 implants from Egypt, India, and Brazil were included in eight papers that made up the systematic review. In several clinical situations, osseodensification outperformed standard drilling in terms of implant durability, bone development, and torque data. Statistical analysis presented the lowest risks, while blinded outcome assessment, allocation concealment, random sequence generation, incomplete outcome data and experimental technique revealed higher risks. Bias assessment found various risks across different components. CONCLUSION: The thorough examination of eight papers demonstrates that osseodensification is a technique with great promise in the field of dental implants. It exhibits superior torque values, bone development, and stability when compared to traditional drilling. The overall results highlight the potential of osseodensification to improve clinical outcomes and advance the science of dental implantology, even in the face of variances in bias concerns.

Accuracy of computer-guided implant surgery in partially edentulous patients: a prospective observational study.

PURPOSE: This study aims to evaluate the amount of distortion using computer-guided implant surgery with 3D printed surgical guides in limited edentulous spaces. MATERIALS AND METHODS: 25 bone level self-tapping implants (Straumann® BL and BLT) were randomly inserted in either distal or intercalary posterior mandibular edentulism using a fully digital protocol and 3D printed surgical guides. Amount of inaccuracy was evaluated after superimposing the 3 coordinates of virtually planned and final implant images, which were obtained using intra-oral scans and scan bodies. Four evaluation parameters were considered: origo-displacement, error depth, apical displacement and angle between the planned and the placed implant. RESULTS: The average of distortion was 0.71 mm for the origo-displacement, 0.36 mm for the error depth, 0.52 mm for the horizontal displacement and 3.34º for the error angle. CONCLUSION: The major reason of exclusion was CBCT artifacts. Results of this study were aligned with the results of previous studies concerning partially edentulous spaces. CAD/CAM manufacturing process did not result in significant distortion whilst the biggest part of distortions originated from the surgical process. The learning curve in computer-guided implant surgery presented an important source of inaccuracy.

Cone-wedge anchored surgical templates for stackable metal guide: a novel technique.

OBJECTIVE: To address the instability in implant surgical guides, this technique proposes an alternative anchoring mechanism in the stackable metal surgical guides utilizing cone-wedge anchors for improved stability. METHODS: Postoperative implant position superimposed onto the preoperatively planned design using Mimics Medical 21.0 and Materialise Magics 24.0 to assess 3D coronal implant deviation, 3D apical implant deviation, and implant angular deviation. RESULTS: Postoperative cone-beam computed tomography (CBCT) revealed a high level of precision in the implant placement, with an average 0.97 mm deviation at implant coronal region, 1.56 mm at implant apexes, and 2.95° angular deviation. CONCLUSION: This technique introduces a novel cone-wedge anchoring mechanism to enhance the stability of stackable metal surgical guide templates, addressing inherent instability issues. The utilization of this approach significantly improves the accuracy of implant placement procedures.

Correlation of two different devices for the evaluation of primary implant stability depending on dental implant length and bone density: An in vitro study.

Non-invasive objective implant stability measurements are needed to determine the appropriate timing of prosthetic fitting after implant placement. We compared the early implant stability results obtained using resonance frequency analysis (RFA) and damping capacity analysis (DCA) depending on the implant length and bone density. Total 60, 4.0 mm diameter implants of various lengths (7.3 mm, 10 mm, and 13 mm) were used. In Group I, low-density bone was described using 15 PCF (0.24 g/cm3) polyurethane bone blocks, and in Group II, 30 PCF (0.48 g/cm3) polyurethane bone blocks were used to describe medium density bone. RFA was performed using an Osstell® Beacon+; DCA was performed using Anycheck®. Measurements were repeated five times for each implant. Statistical significance was set at P <0.05. In Group I, bone density and primary implant stability were positively correlated, while implant length and primary implant stability were positively correlated. In Group II, the implant stability quotient (ISQ) and implant stability test (IST) values in did not change significantly above a certain length. Primary implant stability was positively correlated with bone density and improved with increasing implant length at low bone densities. Compared with the Osstell® Beacon+, the simplicity of Anycheck® was easy to use and accessible.

The precision of drill calibration for dynamic navigation.

OBJECTIVES: To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. METHODS: A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants' entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investigated. The outcome measures for reproducibility were expressed in terms of variability range, average and maximum deviations from the mean distance. RESULTS: A satisfactory inter-rater reproducibility was noted. The precision of the calibration of the tip position in terms of variability range was between 0.3 and 3.7 mm. We noted a tendency towards a higher precision of the calibration process with longer drills. More calibration errors were observed when calibrating long zygomatic implants with non-locking adapters than with pointed drills. Flexible long-pointed drills had low calibration precision that was comparable to the non-flexible short-pointed drills. CONCLUSION: The clinicians should be aware of the calibration error associated with the dynamic navigation placement of dental and zygomatic implants. This should be taken in consideration especially for long implants, short drills, and long drills that have some degree of flexibility. CLINICAL SIGNIFICANCE: Dynamic navigation procedures are associated with an inherent drill calibration error. The manual stability during the calibration process is crucial in minimising this error. In addition, the clinician must never ignore the prescribed accuracy checking procedures after each calibration process.

The three-dimensional stability and accuracy of 3D printing surgical templates: An In Vitro study.

OBJECTIVE: To evaluate the three-dimensional (3D) stability and accuracy of additively manufactured surgical templates fabricated using two different 3D printers and materials. MATERIALS AND METHODS: Forty surgical templates were designed and printed using two different 3D printers: the resin group (n = 20) used a digital light processing (DLP) 3D printer with photopolymer resin, and the metal group (n = 20) employed a selective laser melting (SLM) 3D printer with titanium alloy. All surgical templates were scanned immediately after production and re-digitalized after one month of storage. Similarly, the implant simulations were performed twice. Three-dimensional congruency between the original design and the manufactured surgical templates was quantified using the root mean square (RMS), and the definitive and planned implant positions were determined and compared. RESULTS: At the postproduction stage, the metal templates exhibited higher accuracy than the resin templates (p < 0.001), and these differences persisted after one month of storage (p < 0.001). The resin templates demonstrated a significant decrease in three-dimensional stability after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). No significant differences in implant accuracy were found between the two groups. However, the resin templates showed a significant increase in apical and angular deviations after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). CONCLUSION: Printed metal templates showed higher fabrication accuracy than printed resin templates. The three-dimensional stability and implant accuracy of printed metal templates remained unaffected by one month of storage. CLINICAL SIGNIFICANCE: With superior three-dimensional stability and acceptable implant accuracy, printed metal templates can be considered a viable alternative technique for guided surgery.

On the feasibility of minimally invasive Le Fort I with patient-specific implants: Proof of concept.

A novel approach to Le Fort I osteotomy is presented, integrating patient-specific implants (PSIs), osteosynthesis and cutting guides within a minimally invasive surgical framework, and the accuracy of the procedure is assessed through 3D voxel-based superimposition. The technique was applied in 5 cases. Differences between the surgical plan and final outcome were evaluated as follows: a 2-mm color scale was established to assess the anterior surfaces of the maxilla, mandible and chin, as well as the condylar surfaces. Measurements were made at 8 specific landmarks, and all of them showed a mean difference of less than 1 mm. In conclusion, the described protocol allows for minimally invasive Le Fort I osteotomy using PSIs. Besides, although the accuracy of the results may be limited by the small sample size, the findings are consistent with those reported in the literature. A prospective comparative study is needed to obtain statistically significant results and draw meaningful conclusions.

Effects of Implant Diameter on Implant Stability and Osseointegration in the Early Stage in a Dog Model.

Purpose: To determine the optimal implant diameter under limited bone width by comparing the effects of implants with different diameters on implant stability, peri-implant bone stability, and osseointegration. In addition, to evaluate the reliability of resonance frequency analysis (RFA) in detecting osseointegration and marginal bone level (MBL). Materials and Methods: Mandibular premolars and first molars of seven beagle dogs were extracted. After 8 weeks, their mandibular models and radiographic information were collected to fabricate implant templates. Implant sites were randomly divided into three groups according to diameter: Ø3.3, Ø4.1, and Ø4.8 mm. Implant stability quotient (ISQ) measurement and radiographic evaluation were performed after surgery (baseline) and at 4, 8, and 12 weeks. Three dogs were euthanized at 4 weeks to observe osteogenesis and implant-tissue interface biology. Four dogs were euthanized at 12 weeks to observe osseointegration. Hard tissue sections were prepared to analyze osteogenesis (fluorescence double labeling) and osseointegration (methylene blue-acid fuchsin staining). Results: At baseline and at 4, 8, and 12 weeks, the ISQ values of Ø4.1- and Ø4.8-mm implants did not differ (P > .05), but both had higher values than the Ø3.3-mm implants (P < .05). The mean marginal bone resorption (MBR) associated with Ø3.3-, Ø4.1-, and Ø4.8-mm implants was 0.65 ± 0.58 mm, 0.37 ± 0.28 mm, and 0.73 ± 0.37 mm, respectively. The buccal MBR of Ø4.8-mm implants was significantly higher than that of Ø4.1-mm implants (P < .05). The bone-to-implant contact (BIC) percentage at 12 weeks did not differ for any group (P > .05). The correlation coefficients between the ISQ and MBL of the Ø3.3-, Ø4.1-, and Ø4.8-mm implants were -0.84 (P < .01), -0.90 (P < .001), and -0.93 (P < .001), respectively, while that between the ISQ and BIC was 0.15 (P > .05). Conclusions: During the early healing stage, the performance of Ø4.1- and Ø4.8-mm implants in terms of implant stability was better than that of Ø3.3-mm implants. Implant diameter may not influence BIC percentage. RFA can be used to evaluate implant stability and MBL but is not suitable to assess the degree of osseointegration.

Fratura de implante dentário: relato de caso / Dental implant fracture: case report / Fractura de implante dental: informe de un caso

Com o aumento da população brasileira e consequentemente o número de edêntulos realizando tratamentos reabilitadores com implantes dentários, se tornou frequente aparições de complicações como, por exemplo, sua fratura. O presente trabalho tem por objetivo apresentar as causas prováveis relacionadas a fratura de implante dentário, através de um relato de caso clínico onde pode-se avaliar a condição da fratura apresentada e como foi solucionada. Após a analise do caso clínico, foi constatado que o principal fator que levou a sua fratura foram as sobrecargas oclusais associadas ao mal posicionamento e a qualidade do implante antigo. A partir disso, conclui-se que é de extrema importância o cirurgião dentista estar ciente de todas as possíveis complicações acerca do implante dentário, afim de realizar um bom planejamento cirúrgico diminuindo a taxa de insucesso levando a um bom prognóstico.

With the increase of the Brazilian population and, consequently, the number of edentulous individuals undergoing rehabilitation treatmentes with dental implants, the appearance of complications such as, for example, their fracture has become frequent. The present work aims to presente the probable causes related to dental implant fracture, trough a clinical case report where the condition of the fracture presented and how it was resolved can be evaluated. After analyzing the clinical case, it was found that de main factor that led to its fracture were the occlusal overloads associated with poor positioning and the quality of the old implant. From this , it is concluded that it is extremely important for the dental surgeon to be aware of all possible complications regarding the dental implant, in order to carry out a good surgical planning, reducing the failure rate, leading to a good prognosis.

Con el aumento de la población brasileña y, en consecuencia, del número de personas edéntulas que se someten a tratamientos de rehabilitación con implantes dentales, las complicaciones, como las fracturas, se han vuelto comunes. El presente trabajo tiene como objetivo presentar las probables causas relacionadas con la fractura de implantes dentales, a través del reporte de un caso clínico, donde se puede evaluar la condición de la fractura presentada y la forma en que fue resuelta. Tras analizar el caso clínico, se comprobó que el principal factor que condujo a la fractura fue la sobrecarga oclusal asociada a una mala colocación y a la calidad del implante antiguo. Esto lleva a la conclusión de que es muy importante que el cirujano dental conozca todas las posibles complicaciones de los implantes dentales, para realizar una buena planificación quirúrgica, reduciendo así la tasa de fracasos y consiguiendo un buen pronóstico.

Can the design of the instruments used for undersized osteotomies influence the initial stability of implants installed in low-density bone? An in vitro pilot study.

OBJECTIVES: The aims of this study were to compare the initial implant stability obtained using four different osteotomy techniques in low-density synthetic bone, to evaluate the instrument design in comparison to the implant design, and to determinate a possible correlation between the insertion torque and initial stability quotient (ISQ). MATERIALS AND METHODS: Four groups were identified in accordance with the osteotomy technique used (n = 10 implants per group): group G1, osteotomy using the recommended drilling sequence; group G2, osteotomy using an undersized compactor drill; group G3, osteotomy using an undersized drill; and group G4, osteotomy using universal osseodensification drills. Two polyurethane blocks were used: block 1, with a medullary portion of 10 pounds per cubic foot (PCF 10) and with a 1 mm cortical portion of PCF 40, and block 2, with a medullary of PCF 15 and with a 2 mm cortical portion of PCF 40. Tapered implants of 4 mm in diameter and 11 mm in length were used. The insertion torque (IT) and ISQ were measured. The dimensions of the final instrument used in each group and the dimensions of the implant were used to calculate the total area of each part, and these data were compared. RESULTS: Differences between the four groups were found for IT and ISQ values depending on the technique used for the osteotomy in the two synthetic bone models (p < 0.0001). All groups showed lower values of initial stability in block 1 than in block 2. CONCLUSIONS: Undersized osteotomies with instruments designed according to the implant body significantly increased the initial stability values compared to beds prepared with universal drills and using the drilling sequence standardized by the manufacturer.

Ultrasonic Propagation in a Dental Implant.

Ultrasound techniques can be used to characterize and stimulate dental implant osseointegration. However, the interaction between an ultrasonic wave and the implant-bone interface (IBI) remains unclear. This study-combining experimental and numerical approaches-investigates the propagation of an ultrasonic wave in a dental implant by assessing the amplitude of the displacements along the implant axis. An ultrasonic transducer was excited in a transient regime at 10 MHz. Laser interferometric techniques were employed to measure the amplitude of the displacements, which varied 3.2-8.9 nm along the implant axis. The results demonstrated the propagation of a guided wave mode along the implant axis. The velocity of the first arriving signal was equal to 2110 m.s-1, with frequency components lower than 1 MHz, in agreement with numerical results. Investigating guided wave propagation in dental implants should contribute to improved methods for the characterization and stimulation of the IBI.

Complete-arch fixed reconstruction by means of guided surgery and immediate loading: a retrospective clinical study on 12 patients with 1 year of follow-up.

BACKGROUND: Guided implant surgery is considered as a safe and minimally invasive flapless procedure. However, flapless guided surgery, implant placement in post-extraction sockets and immediate loading of complete-arch fixed reconstructions without artificial gum are still not throughly evaluated. The aim of the present retrospective clinical study was to document the survival and success of complete-arch fixed reconstructions without artificial gum, obtained by means of guided surgery and immediate loading of implants placed also in fresh extraction sockets. METHODS: A total of 12 patients (5 males and 7 females, with a mean age of 50.0 ± 13.8) were enrolled in this study. Implant planning was performed with a guided surgery system (RealGuide®, 3Diemme, Como, Italy), from which 3D-printed surgical templates were fabricated. All implants (Esthetic Line-EL®, C-Tech, Bologna, Italy) were placed through the guides and immediately loaded by means of a temporary fixed full-arch restoration without any artificial gum; the outcome measures were implant stability at placement, implant survival, complications, prosthetic success, soft-tissue stability, and patient satisfaction. RESULTS: One hundred ten implants (65 of them post-extractive) were placed flapless through a guided surgery procedure and then immediately loaded by means of provisional fixed full arches. Successful implant stability at placement was achieved in all cases. After a provisionalization period of 6 months, 72 fixed prosthetic restorations were delivered. Only 2 implants failed to osseointegrate and had to be removed, in one patient, giving a 1-year implant survival rate of 98.2% (108/110 surviving implants); 8/12 prostheses did not undergo any failure or complication during the entire follow-up period. At the 1-year follow-up control, soft-tissue was stable in all patients and showed satesfactory aesthetic results. CONCLUSIONS: Within the limits of this study, complete-arch fixed reconstruction by means of guided surgery and immediate loading of implants placed in fresh extraction sockets appears to be a reliable and successful procedure. Further long-term prospective studies on a larger sample of patients are needed to confirm these positive outcomes.

Do Dietary Supplements and Nutraceuticals Have Effects on Dental Implant Osseointegration? A Scoping Review.

Several factors affect dental implant osseointegration, including surgical issues, bone quality and quantity, and host-related factors, such as patients' nutritional status. Many micronutrients might play a key role in dental implant osseointegration by influencing some alveolar bone parameters, such as healing of the alveolus after tooth extraction. This scoping review aims to summarize the role of dietary supplements in optimizing osseointegration after implant insertion surgery. A technical expert panel (TEP) of 11 medical specialists with expertise in oral surgery, bone metabolism, nutrition, and orthopedic surgery performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP identified micronutrients from the "European Union (EU) Register of nutrition and health claims made on foods" that have a relationship with bone and tooth health, and planned a PubMed search, selecting micronutrients previously identified as MeSH (Medical Subject Headings) terms and adding to each of them the words "dental implants" and "osseointegration". The TEP identified 19 studies concerning vitamin D, magnesium, resveratrol, vitamin C, a mixture of calcium, magnesium, zinc, and vitamin D, and synthetic bone mineral. However, several micronutrients are non-authorized by the "EU Register on nutrition and health claims" for improving bone and/or tooth health. Our scoping review suggests a limited role of nutraceuticals in promoting osseointegration of dental implants, although, in some cases, such as for vitamin D deficiency, there is a clear link among their deficit, reduced osseointegration, and early implant failure, thus requiring an adequate supplementation.

Modified Disk-Up Sinus Reamer for Sinus Floor Elevation and Simultaneous Implant Placement: An Animal Study with Miniature Pigs.

Objective: The disk-up sinus reamer (DSR) is a modified instrument used to elevate the maxillary sinus floor. This study aimed to compare the effects of modified DSR sinus floor elevation (DSFE) with osteotome sinus floor elevation (OSFE), both with simultaneous implant placement. Methods: Twelve miniature pigs were treated with DSFE on one side and OSFE on the other. Implants 9 mm in length were placed in six pigs without grafting, while implants 11 mm in length were placed in the other six pigs with grafting. After submerged healing for 3 months, vertical bone gain (VBG), general and histological observation, and bone contact ratio (BCR) were analyzed. Results: The mean maxillary residual bone height (RBH) when implants were placed was 6.45 ± 0.36 mm. In the no-grafting group, DSFE and OSFE had a similar VBG after 3 months. The grafting group with DSFE recorded a significantly higher VBG (VBG0: 7.83 ± 0.44 mm, VBG1: 7.54 ± 0.40 mm) than the graft group with OSFE (VBG0: 5.45 ± 0.56 mm, VBG1: 4.34 ± 2.15 mm) (p < 0.05). One implant became loose and the sinus mucosa of three pigs appeared metallic in color on the control side (OSFE). Conclusions: The effect of OSFE and DSFE is similar when there is no need for grafting. DSFE seems a better alternative method for sinus floor elevation with grafting when more VBG is needed.

Crestal module design optimization of dental implants: finite element analysis and in vivo studies.

The aim of this study was to evaluate the biomechanical behavior of Bone Level dental implants with four different neck designs in contact with cortical bone. Numerical simulations were performed using a Finite Element Method (FEM) based-model. In order to verify the FEM model, the in silico results were compared with the results obtained from histological analysis performed in an in vivo study with New Zealand rabbits. FEM was performed using a computerized 3D model of Bone Level dental implants inserted in the lower jaw bone with an applied axial load of 100 N. The analysis was performed using four different implant neck designs: even surfaced, screwed, three-ring design and four-ring design. Interface are of bone growth was evaluated by analyzing the Bone-Implant-Contact (BIC) parameter obtained from in vivo histological process and analyzed by Scanning Electron Microscopy (SEM). Bone Level implants were inserted in the rabbit tibia, placing two implants per tibia. The BIC was evaluated after three and six weeks of implantation. FEM studies showed that the three-ring design presented lower values of stress distribution compared to the other studied designs. The lower levels of mechanical stress were then correlated with the in vivo studies, showing that the three-ring design presented the highest BIC value after 3 and 6 weeks of implantation. In silico and in vivo results both concluded that the implants with three-ring neck design presented the best biomechanical and histological behavior in terms of new bone formation, enhanced mechanical stability and optimum osseointegration.

Evaluation of the Peri-Implant Bone Level around Platform-Switched Dental Implants: A Retrospective 3-Year Radiographic Study.

OBJECTIVE: To describe remodeling of the mesial and distal marginal bone level around platform-switched (PS) and platform-matched (PM) dental implants that were sandblasted with large grit and etched with acid over a three-year period. MATERIALS AND METHODS: Digital periapical radiographs were obtained at the following time-points: during Stage I of the surgical placement of dental implants, before loading, immediately after loading (baseline), and one, three, six, 12, and 36 months after loading for measuring the horizontal and vertical marginal bone levels. RESULTS: Sixty implants were successfully osseointegrated during the overall observation period. Vertical marginal bone levels for the PS and PM dental implants were 0.78 ± 0.77 and 0.98 ± 0.81 mm, respectively, whereas the horizontal marginal bone levels for the PS and PM implants were 0.84 ± 0.45 and 0.98 ± 0.68 mm, respectively. During the time leading up to the procedure until 36 months after the procedure, the average vertical marginal bone level resulted in less bone loss for the PS and PM groups-0.96 ± 1.28 and 0.30 ± 1.15 mm, respectively (p < 0.05). The mean levels of the horizontal marginal bone also showed increases of 0.48 ± 1.01 mm in the PS and 0.37 ± 0.77 mm in the PM groups from the time before loading until 36 months after the procedure. However, these increases were not statistically significant (p > 0.05). CONCLUSION: PS dental implants appeared to be more effective than PM implants for minimizing the mean marginal vertical and horizontal marginal bone loss during the three-year period. Regardless of which abutment connection was used, the dental implant in the present retrospective investigation exhibited minimal marginal bone remodeling, thus indicating long-term stability.

Failure rates of mini-implants inserted in the retromolar area.

OBJECTIVE: Anchorage reinforcement is an important issue in orthodontic treatment. There is a lack of evidence regarding the failure rate of mini-implants inserted in the retromolar (RM) area, therefore the purpose of this present study was to evaluate the failure rates of mini-implants inserted in the RM area and to evaluate the factors affecting their stability. MATERIAL AND METHODS: This retrospective cohort study of 102 patients (52 female, 55 male; mean age: 18.6years; SD: 5.2years) that had received 110 RM mini-implants for orthodontic treatment from 1.2.2012 to 1.6.2017 was conducted after IRB approval at the department of orthodontics. Clinical notes and photographic images of the patients were analysed to evaluate the dependent and independent variables. The primary outcome was mini-implant failure. Independent variables of patient related factors, mini-implant related factors, orthodontic related factors, surgical related factors, and maintenance-related factors were evaluated by logistic regression models for association to failure rates. RESULTS: A 23.2% failure rate of mini-implants inserted in the RM area was observed. The patient's right side and inflammation were significantly associated with RM mini-implant failure. The odds ratios (relative risk) for mini-implant failure in the right side, and in mini-implants with inflammation around them were 0.166 and 0.188, respectively. CONCLUSIONS: Failure rate for RM mini-implants were found to be 23.2%. To minimize RM mini-implant failure, clinicians should attempt to reduce inflammation around the mini-implants, especially for mini-implants placed on the right RM area.

Does intraoperative bone density testing correlate with parameters of primary implant stability? A pilot study in minipigs.

Objectives: Bone density, surgical protocol, and implant design are the major determinants of primary stability. The goal of this animal trial was to investigate potential correlations of intraoperative bone density testing with clinical and histologic parameters of primary implant stability. Material and methods: Following extractions of all mandibular premolars and subsequent healing, four implants each were placed in a total of four minipigs. Bone density was determined by applying intraoperative compressive tests using a device named BoneProbe whereas measurements of implant insertion torque and resonance frequency analysis were used for evaluating implant stability. Bone mineral density (BMD) and bone to implant contact were quantified after harvesting mandibular block sections. Spearman rank correlation tests were performed for evaluating correlations (α = .05). Results: Due to variation in clinical measurements, only weak correlations could be identified. A positive correlation was found between the parameters bone to implant contact and BMD (Spearman's rho .53; p = .05) whereas an inverse correlation was observed between BMD and implant stability (Spearman's rho -.61; p = .03). Both BoneProbe measurements in the cortical and trabecular area positively correlated with implant insertion torque (Spearman's rho 0.60; p = .02). A slightly stronger correlation was observed between the average of both BoneProbe measurements and implant insertion torque (Spearman's rho.66; p = .01). Conclusions: While establishing exact relationships among parameters of implant stability and the measurement techniques applied would require greater sample size, intraoperative compressive testing of bone might, despite the weak correlations seen here, be a useful tool for predicting primary implant stability.